Magnetism at single isolated iron atoms implanted in graphite

Mossbauer spectra obtained after implantation of (57)Fe into highly oriented pyrolytic graphite (HOPG) show a combined magnetic and quadrupole interaction with a magnetic hyperfine field B(hf) 32.6 T at 14 K. Though magnetic effects in nominally diamagnetic HOPG have been reported recently, no experiment has previously shown the existence of magnetism at the atomic scale. The results suggest that magnetic ordering occurs by coupling of the Fe magnetic moment to structural and/or electronic magnetic defects induced by the probe atoms' implantation damage.